Weather Service Report


155 
FXUS66 KPQR 022153
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
255 PM PDT THU JUL 2 2015

.SYNOPSIS...STRONG HIGH PRESSURE ALOFT WILL PERSIST OVER THE 
FORECAST AREA THROUGH THE WEEKEND. THE WARMEST DAY OF THE CURRENT 
HOT SPELL APPEARS LIKELY TO BE SUNDAY. SLIGHT COOLING LOOKS POSSIBLE 
EARLY NEXT WEEK AS THE RIDGE WEAKENS SOME...BUT DAYTIME TEMPERATURES 
ARE LIKELY TO REMAIN ABOVE NORMAL. 
&&

.SHORT TERM...NW TO SE ORIENTED RIDGE AXIS EXPECTED TO REMAIN JUST 
TO THE S OF THE FORECAST AREA THROUGH THE WEEKEND. MODELS CONTINUE 
TO SHOW SOME WEAKENING OF THE RIDGE OVER THE REGION RESULTING IN THE 
DEVELOPMENT OF A COL. OVERALL THIS RESULTS IN A CONTINUED RATHER 
STAGNANT WEATHER PATTERN. 

THE LOW LEVEL ONSHORE FLOW IS EXPECTED TO STRENGTHEN A BIT FRI AND 
SAT. UPPER HEIGHTS COMING DOWN A LITTLE...AIDED IN PART BY A 
SHORTWAVE ROTATING AROUND THE W CANADA UPPER LOW...SUGGEST DAYTIME 
HIGHS TO COME DOWN A FEW DEGREES FRI AND SAT. MODEL H8 TEMPS HOWEVER 
REMAIN IN THE 20 TO 22 DEG C RANGE...SO EXPECT HIGH TEMPS LIKELY TO 
REMAIN ABOVE 90 THROUGH SAT IN THE INLAND VALLEYS. AS THE SW CANADA 
SHORTWAVE MOVES ON...UPPER HEIGHTS REBOUND AND H8 TEMPS RETURN TO 
NEAR THURSDAYS NUMBERS. WITH THE QUICK RETURN TO VERY HOT WEATHER 
SUN...WILL EXTEND THE CURRENT HEAT ADVISORY OUT THROUGH SUN. MARINE 
CLOUDS THROUGH THIS PERIOD WILL REMAIN RATHER LIMITED. WITH THE 
STRENGTHENED ONSHORE FLOW EXPECT TO SEE MORE CLOUDS PUSHED UP THE 
LOWER COLUMBIA BY SAT MORNING...THEN LESS CLOUDS AGAIN SUN MORNING. 
 
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...THE EXTENDED PERIOD 
BEGINS WITH HIGH AMPLITUDE 500 MB REX BLOCK OVER THE EASTERN PACIFIC 
AND OR/WA IN WEAK TROUGH OR COL SEPARATING SWRN U.S. RIDGE AND ERN 
PACIFIC/GULF OF AK RIDGE. DESPITE THE WEAK TROUGHINESS...AMS REMAINS 
WARM WITH ABOVE AVERAGE HEIGHTS AND NLY LOW LEVEL FLOW. LITTLE 
CHANGE OCCURS IN OVERALL PATTERN INTO TUESDAY. BY WEDNESDAY...BLOCK 
BEGINS TO BREAK DOWN WITH RIDGING TO THE NORTH AND PACIFIC CUTOFF 
MAKING SLOW EWD PROGRESS TOWARD CNTRL CA CSTLN. DETERMINISTIC MODELS 
AND GEFS MEMBERS IN GOOD AGREEMENT THROUGH TUESDAY...WITH 
DIFFERENCES THEREAFTER MAINLY IN AMPLITUDE OF RIDGING OVER OR/WA/WRN 
CANADA AND POSITION OF ERN PACIFIC CUTOFF. DESPITE THE INCREASING 
UNCERTAINTY MID WEEK...WARM TEMPERATURES NEARLY CERTAIN /10-12 DEG 
ABOVE NORMAL/ BUT INFLUENCE OF ERN PACIFIC CUTOFF PROVIDES A CHANCE 
OF INLAND/MOUNTAIN THUNDERSTORMS TUESDAY-THURSDAY. BRIGHT 
&&

.AVIATION...VFR CONDITIONS WILL PERSIST AT INLAND TAF SITE FOR THE
NEXT 24 HOURS UNDER STABLE WESTERLY FLOW ALOFT. HOWEVER...MARINE
STRATUS LOOKS TO PUSH INLAND UP THE COLUMBIA RIVER TONIGHT AND
COULD BRING PERIODS OF MVFR CIGS TO KKLS AND POSSIBLY KSPB. THE
STRATUS DOES NOT LOOK LIKE IT WILL REACH THE PORTLAND METRO
TERMINALS.

MARINE STRATUS ALONG THE COAST HAS GENERALLY CLEARED LEAVING
WIDESPREAD VFR CONDITIONS. EXPECT VFR CONDITIONS TO CONTINUE
THROUGH AROUND 05Z. WIDESPREAD IFR/LIFR CONDITIONS ARE EXPECTED TO
RETURN TO THE COAST TONIGHT AFTER 05Z. EXPECT FOG/STRATUS TO FILL
IN FROM SOUTH TO NORTH...REACHING KAST AFTER 09Z.

KPDX AND APPROACHES...VFR WILL PERSIST FOR THE NEXT 24 HOURS.

&&

.MARINE...HIGH PRES OVER THE NE PAC AND THERMAL LOW PRES INLAND
WILL CONTINUE TO PRODUCE GUSTY NORTHERLY WINDS INTO THE WEEKEND.
THE STRONGEST WINDS ARE EXPECTED TO CONTINUE OVER THE OUTER WATERS
SO DECIDED TO EXTEND THE SMALL CRAFT ADVISORY TILL SAT MORNING.
ADVISORY LEVEL WINDS OVER THE INNER WATERS WILL CONTINUE THOUGH
LATE THIS EVENING BEFORE FALLING BELOW 20 KT. THERMAL LOW PRES
WILL MOVE OFFSHORE THIS WEEKEND WITH WINDS ACROSS ALL WATERS
REMAINING BELOW 20 KT INTO NEXT WEEK.

EXPECT PERIODS OF STEEP AND CHOPPY SEAS OVER THE OUTER WATERS TO
CONTINUE INTO THIS WEEKEND WITH COMBINED SEAS OF 7 TO 8 FT AND A
DOMINATE PERIOD AROUND 8 SECONDS. AS SUCH...DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY TILL SAT MORNING FOR SQUARE SEAS. STRONG
WINDS OFF OF VANCOUVER ISLAND WILL PRODUCE A BUILDING NW SWELL
THIS WEEKEND THAT COULD PUSH SEAS ABOVE 10 FT. SEAS WILL SUBSIDE
EARLY NEXT WEEK TO AROUND 4 TO 5 FT.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HEAT ADVISORY UNTIL 6 PM PDT SUNDAY FOR NW OREGON INTERIOR 
     LOWLANDS...CASCADE FOOTHILLS...AND CENTRAL OREGON COAST
     RANGE.

WA...HEAT ADVISORY UNTIL 6 PM PDT SUNDAY FOR LOWER COLUMBIA AND
     SW WASHINGTON INTERIOR LOWLANDS.

PZ...SMALL CRAFT ADVISORY FOR WINDS AND HAZARDOUS SEAS UNTIL 7 AM
     PDT SATURDAY FOR WATERS FROM CAPE SHOALWATER TO FLORENCE 
     FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT THIS EVENING 
     FOR COASTAL WATERS FROM CAPE SHOALWATER TO FLORENCE OUT 
     10 NM.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON 
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS 
COMMONLY REFERRED TO AS THE FORECAST AREA.

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